1. Field of the Invention
The present invention relates to a digital image interpolation, and more particularly, to an image interpolation method and apparatus thereof enabling to provide an interpolated image of high definition.
2. Background of the Related Art
Generally, interpolation of a image signal is a process of generating large-sized image data from small-sized data, which is applicable to various applied fields of home appliances such as digital TV, camcorder, and the like as well as PC application software, image analyzing system, and the like. Simple interpolation includes an interpolation through linear filtering, bi-linear interpolation, bi-cubic interpolation, and the like. Yet, such interpolations fail to settle the blurring of edge as a basic problem in image interpolation so far.
Edge-directed interpolation by finding an edge of an image is proposed by the following.
[1] J. Allebach and P. W. Wong, “Edge-directed interpolation”, international conference or, image processing'96, vol. 3, pp. 707–710, 1996.
[2] X. Li and M. T. Orchard, “New edge-directed interpolation”, international conference on image processing'2000, vol. 2, pp. 311–314, 2000.
However, the interpolation in [1] includes the steps of providing an edge map in an image of low resolution, transforming the provided edge map into a map of high resolution, and carrying out rendering and correction using the attained edge map, thereby requiring lots of calculation. Meanwhile, the interpolation in [2] is to reduce lots of calculation in the interpolation in [1], which includes the steps of finding a local statistical characteristic of an image and finding an interpolation filter coefficient using the found characteristic. Yet, the interpolation in [2] requires lots of calculation in finding the statistical characteristic and filter coefficient as well. Moreover, when an estimated direction of the edge is wrong due to a noise existing in the image or the like, geometric distortion occurs in the interpolated image.